1. Field of the Invention
This invention is directed to a system and process for measuring Mueller matrix elements, in particular, with utilization in biological warfare. The present invention is also directed for use in quality control for manufacturing of micron-sized particles of various shapes to determine the extent of deviation from design parameters for members of a batch of particles, for use in rapid classification of the types of cells contained in a particular tumor or other biological samples, and for use in quality control of various powders manufactured for pharmaceuticals and other applications.
2. Description of the Background
The Mueller matrix is the transfer matrix in the Stokes algebra that describes the polarization of natural light. It can be used for comparison with theoretical calculations as well as the determination of material parameters. The Mueller matrix is an important parameter in the study of polarization configuration associated with light-scattering and radiative transfer processes.
Mueller matrix elements are used for such systems as small particle, or a collection of particles, or any other scattering system to give all the characteristics of that system for scattering polarized light (Bohren and Huffman, 1983; van der Hulst, 1957). It has been shown both experimentally and theoretically, that measuring some of these parameters as a function of scattering angle, gives information on the size, shape and optical constants of collections of biological particles (e.g., Bohren, 1983; Van der Merwe et al. 1992, 1995).
One application of such measurement produced a rapid measure of the toxicity of certain compounds of bacteria (Bronk et al. 2001) and rapid measurement of changes of bacterial cell size in vivo (Van der Merwe et al., 1997). As comparable optics become available for the IR ranges (e.g. about 10 micrometers) suitable for large cells, as are now available in the visible and near IR, similar measurements will have important medical applications for rapid examination of disaggregated mammalian cells (e.g., from biopsies) after various treatments.
In this time of war and terrorism, preparation for new methods of attack on armed forces is important. Attack by deliberate exposure to a biological pathogen is likely to be in the form of an airborne microorganism. Thus, there is a need for an efficient and inexpensive method and apparatus for obtaining classification information of an aerosol.